.Net 3.5 SP1 is supportet as of SP2 of Platform 7.0 (kb46349).
But SQL 2008 is not! Are you using SQL2005?
SMP7 on SQL2008 runs, but leads to very strange behaviour. Especially with filters.
The only filter which shows the AD-imported clients is "Windows Computers with no Altiris Agent Installed". Because all (or the most) of the others show just the "managed" clients, which means with Altiris Agent installed.